Management of shared risk group identifiers for multi-layer transport networks with multi-tier resources

ABSTRACT

A system includes a plurality of resources. A network analysis device is configured to identify a shared risk between at least two of the resources. A method includes arranging a plurality of resources in a resource group, identifying, by at least one network analysis device, a shared risk between at least two of the plurality of resources, and assigning a shared risk identifier to each resource having the shared.

BACKGROUND

Network provisioning involves a service provider preparing and equippinga network to provide network services to customers. Provisioners may beindividuals who monitor network resources and provision the networkaccordingly. For example, a provisioner may determine whether morenetwork resources are required to service a specific geographic areabased on information available to the provisioner. The service providermay require that the provisioned network comply with various rules. Forexample, the service provider may require that the network implement adiversity scheme. Diversity in a network means that two or morecommunications channels are used to communicate between network devices.If one channel fails, communication between the network devices is notlost because another channel remains active.

Historically, it has been difficult for provisioners to provision to thenetwork to properly comply with the service provider's diversity schemesimply because it is difficult to track the physical location of eachnetwork resource and diversity relationship among all resources. Whilethe network may seem to comply with the diversity scheme, manysupposedly diverse channels share a similar risk. For example, twodifferent fibers may be used to communicate between two network devices,giving the appearance of diversity. However, two seemingly diverse fiberoptic cables may run through the same pipe before reaching theireventual destination. As a result, the two fiber optic cables share asimilar risk (e.g., a single incidence could damage the pipe and severall of the fiber optic cables within that pipe). Accordingly, a systemis needed that helps provisioners properly provision a network to complywith the service provider's diversity scheme.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary system for identifying shared risksamong resources in a resource group;

FIG. 2A illustrates an exemplary list of shared risk identifiers thatmay be generated by a network analysis device;

FIG. 2B illustrates an exemplary list of sharing scopes that may begenerated by the network analysis device;

FIG. 2C illustrates an exemplary table of final shared risk identifiersthat may be assigned by the network analysis device;

FIG. 3A illustrates an exemplary system for identifying shared risksamong resources in a resource group having policies;

FIG. 3B illustrates an exemplary resource group tree indicatingcross-tier dependency and policy violations;

FIG. 3C illustrates an exemplary list of sharing scopes for theexemplary resources group of FIG. 3B;

FIG. 3D illustrates an exemplary list of final shared risk identifiersfor the exemplary multi-tier resource group of FIG. 3A; and

FIG. 4 illustrates an exemplary process for identifying final sharedrisk identifiers for the exemplary multi-tier resource group of FIG. 3A.

DETAILED DESCRIPTION

An exemplary system includes a plurality of resources. A networkanalysis device is configured to identify a shared risk between at leasttwo of the resources. A shared risk may exist if two or more same-tierresources rely upon the same higher-tier resource. For example, twosame-tier resources share the same risk if they are at least partiallyphysically contained within the same higher-tier resource. For example,two fiber optic cables share a risk with one another when the two fiberoptic cables at least partially extend through one conduit.Alternatively, two same-tier resources may share the same risk if theydepend upon the same higher-tier resource for operational support. Forexample, two circuit packs share the same risk with one another if theyare powered by the same power supply. Moreover, a service provider maydefine policy-based risks even if there is no physical shared risk. Forexample, a policy may state that two resources within a predetermineddistance from one another for a minimum length share the same risk. Atelecommunications service provider may use such a system to ensure thata network is properly provisioned to meet various diversityrequirements.

FIG. 1 illustrates an exemplary system 100 having a physical networkdatabase 105 storing information about a plurality of resources in anetwork and a policy database 110 storing one or more policies that maygovern the resources. The system 100 further includes a network analysisdevice 115 in communication with the physical network database 105 andthe policy database 110. The system 100 may take many different formsand include multiple and/or alternate components and facilities. Whilean exemplary system 100 is shown in FIG. 1, the exemplary componentsillustrated in FIG. 1 are not intended to be limiting. Indeed,additional or alternative components and/or implementations may be used.

The physical network database 105 may store information about theplurality of resources. For example, the physical network database 105may define the resources as part of a multi-tier resource group 120. Ina multi-tier resource group 120, each of the resources is assigned atier depending on the type of resource. Various resources may be dividedinto one or more multi-tier resource groups depending on a networkoperator's diversity requirements, in which case the process specifiedherein may apply to each separate multi-tier resource group to derivethe final shared risk group identifiers. In one exemplary approach, theresources in Tier 1 may represent a fiber optic cable. The resources inTier 2, then, may be conduits through which the fiber optic cables pass(e.g., pipes in a city). Continuing with that exemplary approach, theresources in Tier 3 may be bridges or tunnels that carry the pipes overor through a body of water. The tiers in a multi-tier resource group 120may have different or alternative meanings with respect to theresources. For instance, the Tier 2 resources may include power suppliesthat operationally support the Tier 1 fiber optic cables.

As illustrated in FIG. 1, the physical relationship of the resources toone another are represented by the physical network database 105 as aresource group tree. In the resource group tree, each resource in aspecific tier may be graphically represented having a specific shape. Inthe exemplary illustration of FIG. 1, each resource on Tier 1 isgraphically represented by a circle, each resource on Tier 2 isgraphically represented by a square, and each resource on Tier 3 isgraphically represented by an octagon. The physical relationship of eachresource may be represented by a line connecting a resource in one tierto a resource in another tier. For example, in FIG. 1, a line connectsresource A2 to resource B1, meaning that resource A2 is at leastpartially physically contained within resource B1. Alternatively, theline may indicate that resource A2 is operationally supported byresource B1. Moreover, a line connects resource A2 to resource B2,meaning that, at some point, resource A2 is at least partiallyphysically contained within or operationally supported by resource B2.Furthermore, a line connects resource A3 to resource B2, meaning thatresource A3 relies upon resource B3 for physical or operational support.However, the physical and operational relationships of the resources maybe represented in another format, such as in a table. Moreover, althoughthree tiers are illustrated in FIG. 1, the multi-tier resource group 120may have any number of tiers.

At various times or for various distances, a lower-tier resource mayrely upon multiple higher-tier resources for operational or physicalsupport. For example, referring to FIG. 1, resource A2 may be a fiberoptic cable, resources B1 and B2 may be separate pipes, and resource C1may be a bridge. In the multi-tier resource group 120 of FIG. 1, thefiber optic cable A2 may be within the pipe B1 for 100 feet beforecrossing the bridge C1. On the other side of the bridge C1, the fiberoptic cable A2 may enter the pipe B2 for 200 hundred feet. Therefore,the fiber optic cable A2 is in the pipe B1 at the same time the fiberoptic cable A2 is crossing the bridge C1.

The physical network database 105 may store information about eachresource. For example, the physical network database 105 may store aname of the resource (e.g., “A1,” “A2,” “B1,” “B2,” “C1,” “C2,” etc.),the type of resource (e.g., fiber, fiber optic cable, conduct, etc.),the geographical location of the resource, shared risk identifiers(e.g., “a1” for resource A1, “a2” for resource A2, and so on) indicatingthat the resource shares one or more physical or policy-based risk withother resources as discussed in greater detail below, the physicalrelationship between each of the resources, the operational relationshipbetween each of the resources, and the like. As illustrated in FIG. 1,continuing with the previous example, resource A2 is a fiber cable thatmay be carried in the conduit represented by resource B1, which runsthrough the bridge represented by resource C1.

The policy database 110 may store policies that can be used to governthe resources. The policies may include one or more standard policiesset forth by a government agency or standards body. Alternatively, in atelecommunications network, a service provider may determine one or moreof the policies. The policy may define various rules regarding the waythe network may be provisioned. For example, one policy may defineminimum quality of service requirements, including diversity schemes, tobe implemented in the network. Therefore, due to a policy violation, tworesources may lack diversity even if the resources are physicallydiverse.

For example, separate fibers may experience a shared risk if both fibersare disposed within the same fiber optic cable. Therefore, any group oflower-tier resources (e.g., Tier 1 resources as illustrated in FIG. 1)that rely upon the same higher-tier resource (e.g., Tier 2 or Tier 3 asillustrated in FIG. 1) lack physical and operational diversity. However,a group of resources need not be physically disposed within anotherresource or operationally supported by another resource to lackdiversity. For example, a policy may define that same-tier resourceslack diversity if they are within a predetermined distance from oneanother for a minimum length. The policy, in one exemplary approach, maydefine a shared risk as existing between two Tier 1 resources that arewithin 20 feet of one another for a distance of at least 30 feet. Inthis exemplary approach, if the fiber optic cables are Tier 1 resources,any two fiber optic cables that are within 20 feet of one another for adistance of at least 30 feet are assumed to share a risk, even thoughthe two Tier 1 fiber optic cables may not extend through the same Tier 2conduit.

Databases, data repositories or other data stores described herein, suchas the physical network database 105 and the policy database 110, mayinclude various kinds of mechanisms for storing, accessing, andretrieving various kinds of data, including a hierarchical database, aset of files in a file system, an application database in a proprietaryformat, a relational database management system (RDBMS), etc. Each suchdata store is generally included within a computing device employing acomputer operating system such as one of those mentioned above, and areaccessed via a network in any one or more of a variety of manners, as isknown. A file system may be accessible from a computer operating system,and may include files stored in various formats. An RDBMS generallyemploys the known Structured Query Language (SQL) in addition to alanguage for creating, storing, editing, and executing storedprocedures, such as the PL/SQL language mentioned above.

The network analysis device 115 may include a computing device incommunication with the physical network database 105 and the policydatabase 110. The network analysis device 115 may be configured toidentify a shared risk between at least two network resources. Forexample, using the resource group tree or table in the physical networkdatabase 105 and information in the policy database 110, the networkanalysis device 115 may be configured to identify physical shared risks(e.g., two lower-tier resources are physically contained within the samehigher-tier resources), operational shared risk (e.g., two lower-tierresources rely upon the same higher-tier resource to operate), andpolicy-based shared risks (e.g., two same-tier resources are within apredetermined distance from one another for a minimum length) for eachresource in a multi-tier resource group 120.

Once the shared risk is identified, the network analysis device 115 maybe configured to associate the shared risk with a shared riskidentifier, and assign the shared risk identifier to each resource inthe resource group sharing the same risk. In the exemplary resourcegroup tree of FIG. 1, resources A2 and A3 rely upon resource B2.Therefore, the network analysis device 115 may be configured to identifythat resources A2 and A3 share a risk and assign resources A2 and A3 thesame shared risk identifier, as discussed in greater detail below. Thenetwork analysis device 115 may be further configured to store theshared risk identifier in the physical network database 105.

The network analysis device 115 may further be configured to assign abasic shared risk identifier to each single resource of interest in anetwork because each resource itself represents a shared risk. Forinstance, each fiber cable represents a shared risk for all fibers inthe cable. The network analysis device 115 may assign the basic sharedrisk identifiers to all resources under consideration. For examples, allthe shared risk identifiers (e.g., in parentheses in FIGS. 1 and 3A)associated with each resource in FIG. 1 and FIG. 3A are basic sharedrisk identifiers assigned by network analysis device 115.

Besides identifying physical shared risks, the network analysis device115 may be configured to access one or more policies stored in thepolicy database 110 for each tier of resources and apply one or more ofthe policies to the resources on the same tier to identify policy-basedshared risks. The network analysis device 115 may be configured toidentify closed risk-sharing groups for each policy on every tier. Theclosed risk sharing group may include any subset of the resources on atier in which every possible pair are involved in at least one policyviolation instance. Each closed risk sharing group may be assigned a newpolicy-based shared risk identifier by the network analysis device 115to represent the shared risk of all resources in the closed risk sharinggroup. For example, using the information in the physical networkdatabase 105, the network analysis device 115 may be configured todetermine whether two or more resources violate the policy forming aclosed risk sharing group, and thus, share the same policy-based risk.Once all closed risk sharing groups are identified, the network analysisdevice 115 may be configured to assign policy-based share riskidentifiers to the closed risk sharing groups and associate eachpolicy-based shared risk identifier to all the resources in the closedrisk sharing group.

In general, computing systems and/or devices, such as the networkanalysis device 115, may employ any of a number of well known computeroperating systems, including, but by no means limited to, known versionsand/or varieties of the Microsoft Windows® operating system, the Unixoperating system (e.g., the Solaris® operating system distributed by SunMicrosystems of Menlo Park, Calif.), the AIX UNIX operating systemdistributed by International Business Machines of Armonk, N.Y., and theLinux operating system. Examples of computing devices include, withoutlimitation, a computer workstation, a server, a desktop, notebook,laptop, or handheld computer, or some other known computing systemand/or device.

Computing devices generally include computer-executable instructions,where the instructions may be executable by one or more computingdevices such as those listed above. Computer-executable instructions maybe compiled or interpreted from computer programs created using avariety of well known programming languages and/or technologies,including, without limitation, and either alone or in combination,Java™, C, C++, Visual Basic, Java Script, Perl, etc. In general, aprocessor (e.g., a microprocessor) receives instructions, e.g., from amemory, a computer-readable medium, etc., and executes theseinstructions, thereby performing one or more processes, including one ormore of the processes described herein. Such instructions and other datamay be stored and transmitted using a variety of known computer-readablemedia.

A computer-readable medium (also referred to as a processor-readablemedium) includes any non-transitory (e.g., tangible) medium thatparticipates in providing data (e.g., instructions) that may be read bya computer (e.g., by a processor of a computer). Such a medium may takemany forms, including, but not limited to, non-volatile media andvolatile media. Non-volatile media may include, for example, optical ormagnetic disks and other persistent memory. Volatile media may include,for example, dynamic random access memory (DRAM), which typicallyconstitutes a main memory. Such instructions may be transmitted by oneor more transmission media, including coaxial cables, copper wire andfiber optics, including the wires that comprise a system bus coupled toa processor of a computer. Common forms of computer-readable mediainclude, for example, a floppy disk, a flexible disk, hard disk,magnetic tape, any other magnetic medium, a CD-ROM, DVD, any otheroptical medium, punch cards, paper tape, any other physical medium withpatterns of holes, a RAM, a PROM, an EPROM, a FLASH-EEPROM, any othermemory chip or cartridge, or any other medium from which a computer canread.

In some examples, system elements may be implemented ascomputer-readable instructions (e.g., software) on one or more computingdevices (e.g., servers, personal computers, etc.), stored on computerreadable media associated therewith (e.g., disks, memories, etc.). Acomputer program product may comprise such instructions stored oncomputer readable media for carrying out the functions described herein.

The network analysis device 115 may perform various processes toidentify shared risks among resources in a multi-tier resource group120. With reference to FIGS. 2A-2C, the network analysis device 115 maybe configured to determine the basic shared risk identifier of eachresource in the resource group. The network analysis device 115 may beconfigured to assign the basic shared risk identifier to each resourcethat may not already have basic shared risk identifier assigned. Thenetwork analysis device 115 may further be configured to list the sharedrisk identifiers of higher-tier resources that each lowest-tier resourceat least partially relies upon directly or indirectly.

FIG. 2A includes an exemplary list of shared risk identifiers for Tier 1resources that may be generated by the network analysis device 115. Withthe list of shared risk identifiers, the network analysis device 115 mayidentify shared risks for each Tier 1 resource. In the exemplaryimplementation illustrated in FIG. 1, resource A2 has two branches.First, resource A2 at least partially relies upon resource B1, whichitself at least partially relies upon resource C1. Second, resource A2also at least partially relies upon resource B2. Therefore, for resourceA2, which is one of the resources on the lowest tier (i.e., Tier 1), thenetwork analysis device 115 is configured to generate two lists ofshared risk identifiers for resource A2. These two lists, for instance,may include shared risk identifiers a2, b1, c1, and a2, b2. The networkanalysis device 115 may be configured to iteratively repeat this portionof the process for each resource in the lowest tier. The complete listof shared risk identifiers within which each Tier 1 resource of FIG. 1is at least partially contained or operationally supported by isillustrated at FIG. 2A.

Referring now to FIG. 2B, to eliminate redundancy, the network analysisdevice 115 may be further configured to identify a sharing scope of eachhigher-tier resource. The sharing scope may only apply to higher-tierresources directly or indirectly containing or operationally supportingmultiple lowest-tier resources. The sharing scope for each higher-tierresource may be defined to be the set of lowest-tier resources that arecontained or operationally supported by the higher-tier resource. Forinstance, in FIG. 1, there are three Tier 2 resources that contain oroperationally support multiple Tier 1 resources, (i.e., the resourceshaving shared risk identifiers of b2, b4, and b5), and one Tier 3resource that contains or operationally supports multiple Tier 1resources (i.e., having a shared risk identifier of c3) as shown in FIG.2B. When the shared Tier 1 resources of one of the Tier 2 resources arefully contained within the sharing scope of one of the Tier 3 resources,the shared risk identifier for the Tier 2 resource will not beconsidered for final shared risk identifier selection (i.e., the sharedrisk identifier of the Tier 2 resource will not be applied to the Tier 1resource it contains or operationally supports). Rather, the shared riskidentifier of the Tier 3 resource will be applied. Therefore, in FIG.2B, the shared risk identifier of b4 will be eliminated because itssharing scope is a subset of that of resource C3. Accordingly, thenetwork analysis device 115 will apply the shared risk identifier of c3to resources A4, A18, and A20.

To identify sharing scopes, the network analysis device 115 may list thelower-tier resources that rely upon each higher-tier resource. Asillustrated in FIG. 1, the network analysis device 115 may be configuredto determine that higher-tier resource B2 at least partially physicallycontains or operationally supports resources A2 and A3. Higher-tierresource C3 at least partially physically contains or physicallysupports resources B4 and B6, which in turn at least partially containor physically supports resources A4, A18, and A20. Also illustrated inFIG. 1, resource B4 includes resources A4 and A18. Moreover, resource C3includes resources A4, A18, and A20. The network analysis device 115 maybe configured to identify that a sharing scope exists between resourcesB4 and C3 since each lower-tier resource contained with resource B4(e.g., A4 and A18) is also included in resource C3. The network analysisdevice 115 may be configured to iteratively repeat this portion of theprocess for each higher-tier resource. The complete list of sharingscopes for the exemplary multi-tier resource group 120 of FIG. 1 isillustrated in FIG. 2B.

FIG. 2C includes an exemplary table of shared risk identifiers. Afterthe sharing scopes have been identified for each higher-tier resource,the network analysis device 115 may be configured to assign the sharedrisk identifier to each resource in one or more tiers. Referring againto the exemplary multi-tier resource tree of FIG. 1, resource A2 may beassigned a shared risk identifier equivalent to the shared riskidentifier for resource C1 (i.e., “c1”) because resource C1 is thehighest-tier resource that resource A2 at least partially relies upon.However, as previously discussed with respect to FIG. 2A, resource A2 astwo separate chains—resource C1 is the highest-tier resource of onechain, and resource B2 is the highest-tier resource of the second chain.Therefore, resource A2 may also be assigned the shared risk identifierof resource B2 (i.e., “b2”). The network analysis device 115 may repeatthis portion of the process for each of the lowest-tier resources.Although not illustrated in FIG. 2C, the network analysis device 115 mayfurther repeat this portion of the process for higher-tier resources.

FIG. 3A illustrates an exemplary policy scheme applied to anothermulti-tier resource group with policies. In addition to identifyingphysical and operational relationships between the resources, thenetwork analysis device 115 may be further configured to identifypolicy-based relationships between the resources on the same tier,including policy violations that indicate that a shared risk existsbetween resources. For instance, the Tier 1 resources may be governed bya Tier 1 policy that states, for example, that Tier 1 resources that arewithin 20 feet of one another for a distance of at least 30 feet sharethe same risk. Moreover, the Tier 2 resources may be governed by a Tier2 policy. For clarity, only two tiers are illustrated in FIG. 3A. Thus,the resource group tree of FIG. 3A may include additional tiers. Thenetwork analysis device 115 may be configured to compare informationabout each resource from the physical network database 105 to theinformation stored in the policy database 110 to determine whether anyresources violate any of the policies and assign a policy-based sharedrisk identifier to resources that share the same policy-based risk.

FIG. 3B illustrates an exemplary resource group tree showing policyviolations in the exemplary multi-tier resource group 120 of FIG. 3A. Asillustrated, the resources in the resource group are bound by twopolicies: one for Tier 1 and another for Tier 2. The network analysisdevice 115 may be configured to carry out the process discussed withrespect to FIGS. 1 and 2 to obtain policy-based shared risk identifiersP1 and P2 for Tier 1, and P3 and P4 for Tier 2. For instance, thenetwork analysis device 115 may be configured to identify closedrisk-sharing groups for each policy on every tier, determine whether twoor more resources violate the policy forming a closed risk sharinggroup, and thus, share the same policy-based risk, and assignpolicy-based share risk identifiers to the closed risk sharing groupsand associate each policy-based shared risk identifier to all theresources in the closed risk sharing group. Each policy-based share riskidentifier may indicate that a violation is detected among a set of theresources on that tier. For example, two lines extend from P1 toresources A2 and A4, which means resources A2 and A4 violate the Tier 1policy (e.g., resources A2 and A4 are within 20 feet of one another forat least 30 feet). Similarly, the lines extending from P4 to resourcesB4 and B6 indicate that resources B4 and B6 violate the Tier 2 policy.

FIG. 3C illustrates an exemplary list of sharing scopes for theexemplary multi-tier resource group 120 of FIG. 3B. The sharing scopesof FIG. 3C may be determined by the network analysis device 115 the sameway as previously discussed with regard to FIG. 2B. In the exemplaryapproach of FIG. 3C, the sharing scope of shared risk identifier b4 isfully contained in the sharing scope of policy-based shared riskidentifier P4. Therefore, the network analysis device 115 will not useb4 in its down stream processing.

In one exemplary implementation, as illustrated in FIG. 3B, resource A2at least partially relies upon resources B1 and B2, and violates Tier 1policy at identifier P1. But, the sharing scopes of resource B2 (i.e.,b2) and P1 are fully contained in the scope of P3. Therefore, the finalshared risk identifiers to be assigned to A2 are “b1” and “P3.”Similarly, the network analysis device 115 may assign shared riskidentifiers of “b5” and “P4” to resource A20. To reduce redundancy, thenetwork analysis device 115 may be configured to account for sharingscopes as previously discussed. If a sharing scope exists between aresource and a same-tier or higher-tier policy, the network analysisdevice 115 may select the shared risk identifier of the policy as theshared risk identifier instead of the higher-tier resource because thesharing scope of the shared risk identifier of the higher-tier resourcesis a subset of that of the shared risk identifier of the policy. Aspreviously discussed, resource B2 and policy P3 define a sharing scope(e.g., all of the lower-tier resources that are at least partiallycontained within B2 also violate policy P3). In this exemplary approach,the network analysis device 115 may be configured to assign thepolicy-based shared risk identifier of P3 instead of the shared riskidentifier of resource B2. Further, the network analysis device 115 maybe configured to assign the shared risk identifiers of resource B2 andpolicy P3 despite the sharing scope.

FIG. 3D illustrates an exemplary list of final shared risk identifiersfor the exemplary multi-tier resource group of FIG. 3A. The networkanalysis device 115 may be configured to assign the shared riskidentifier of the highest-tier resource in which each of the lowest-tierresource at least partially relies upon. Moreover, the network analysisdevice 115 may be configured to assign the shared risk identifier of apolicy to resources that violates that policy.

The network analysis device 115 may be further configured to weigh orprioritize the risk and apply a policy accordingly. For example, thenetwork analysis device 115 may identify a greater risk based on variousfactors including physical, environmental, and geographical, etc. In oneexemplary approach, the network analysis device 115 may determine thatolder resources have a greater risk than newer resources. If theresource includes a fiber optic cable, the network analysis device mayapply more stringent policies to older fiber optic cables (e.g., olderfiber optic cables that are within 40 feet of one another for a distanceof at least 30 feet share a risk). Also, environment may play a factorwhen weighing or prioritizing risk. For example, the network analysisdevice 115 may apply a different policy to resources that are exposed tothe elements (e.g., rain, snow, lightning strikes, etc.) or that travelunder water (e.g., risk of ships dropping anchor and damaging theresource, risk of water damage, and the like). Further, the networkanalysis device 115 may apply a different policy to resources that aredisposed in densely populated urban areas where resources are morelikely to be closer together.

In addition, the network analysis device 115 may be configured to weighthe shared risk based on various circumstances. For instance, a firstgroup of resources that are within 20 feet of one another for a distanceof 200 feet shares a greater risk than a second group of resources thatare within 20 feet of one another for only 30 feet. While a shared riskexists in both circumstances, the shared risk identifier assigned by thenetwork analysis device 115 may reflect the weight of the shared risk.For instance, the shared risk identifier assigned may be different forresources that are within 20 feet of one another for over 200 feet whencompared to other same-tier resources that are only within 20 feet ofone another for only 30 feet.

FIG. 4 illustrates an exemplary process for identifying a shared riskbetween at least two of the resources. In one exemplary approach, onlythe shared risk identifier of the highest-tier source that thelowest-tier resource relies upon may be considered as the shared riskidentifier assigned to the lowest-tier resource.

Block 405 may include identifying resources in a multi-tier resourcegroup. Each resource may be associated with a specific tier. Moreover,each tier in the resource group may be governed by a policy, aspreviously discussed.

Decision point 410 may include determining whether two or more same-tierresources violate the same-tier policy. Resources that violate thepolicy may be indentified as being part of a closed risk sharing groupfor each policy on each tier. As previously discussed, the closed risksharing group may include any subset of the resources on a tier in whichevery possible pair is involved in at least one policy violationinstance.

If two or more resources violate the same-tier policy, the process 400moves to block 415, which may include assigning a policy-based sharedrisk identifier to the resources that violate the policy. For instance,the network analysis device 115 may assign the policy-based shared riskidentifier to the resources that violate the same-tier policy.Therefore, each closed risk sharing group may be assigned a newpolicy-based shared risk identifier by the network analysis device 115to represent the shared risk of all resources in the closed risk sharinggroup.

If no same-tier resources violate the policy, or after the policy-basedshared risk identifier has been assigned, the process 400 may move toblock 420. Block 420 may include assigning the shared risk identifierfor the highest-tier resource that each lowest-tier resource reliesupon. If the lowest-tier resource is a “root-only” resource (i.e., thelowest-tier resource does not rely upon any higher-tier resources), thenetwork analysis device 115 may assign the shared risk identifier of thelowest-tier resource to itself. If the lowest-tier resource is apart ofa single-branch tree (i.e., a Tier 1 resource that only relies upon onechain of upper tier resources), the network analysis device 115 mayassign the shared risk identifier of the highest tier resource on thechain to the Tier 1 resource. If the Tier 1 resource is part of amultiple-branch tree (i.e., the Tier 1 resource involves, directly orindirectly, in policy violation or relies upon upper-tier resources thatalso tend to other Tier 1 resources), the network analysis device 115may assign multiple shared risk identifiers to the Tier 1 resource(e.g., the share risk identifier of the highest-tier resource of eachbranch).

Block 425 may include accounting for sharing scopes. As previouslydiscussed, the sharing scope for each higher-tier resource may bedefined to be the set of lowest-tier resources that are contained oroperationally supported by the higher-tier resource. Once identified,the network analysis device 115 may be configured to remove anyredundancy by accounting for the sharing scopes.

The process 400 may be iteratively performed for each Tier 1 resource.When each Tier 1 resource is assigned one or more shared riskidentifiers, the process 400 may end after block 425. When the process400 is applied to an exemplary resource group as illustrated in FIG. 3B,the end result may be a table as illustrated in FIG. 3D.

In one exemplary approach, the process 400 previously described may beapplied to each multi-tier resource group in a network. For instance,the resources may be divided into multiple multi-tier resource groups.The number of multi-tier resource groups and the resources contained ineach group may be based on a network operator's diversity or otherrequirements. The process 400 previously described may be applied toeach of the multi-tier resource groups to identify the final shared riskidentifiers for each of the lowest-tier resources in each of themulti-tier resource groups.

The concepts described herein may further apply to a routing controlplane. In routing, the control plane is a part of the routingarchitecture that draws the network map via, for example, a networktable that defines what to do with incoming data. In order to implementa diversity scheme, whether physical, policy-based, or both, the routingcontrol plane may use the shared risk identifiers to determine how datashould be routed in the network, such as an optical transport network.

In one exemplary approach, the network analysis device 115 may beconfigured to assign a shared risk link group identifier to each controlplane link in the network. The control plane link may include one ormore Tier 1 resources from different resource groups. Thus, the sharedrisk link group identifier may be the union of each the shared riskidentifiers for each resource in the control plane link. The shared risklink group identifier may be configured on the control plane to ensureend-to-end diversity for various protection and restoration schemes.

However, the shared risk link group identifier on a control plane linkmay include more shared risk identifiers than a control plane capablenode can handle (e.g., for lack of memory). Therefore, the networkanalysis device 115 may be configured to assign a combination sharedrisk identifier to replace a group of shared risk identifiers previouslyincluded in the shared risk link group identifier. In one exemplaryapproach, the combination shared risk identifier may only be assigned toa group of shared risk identifiers, which do not contain anypolicy-based shared risk identifier. Moreover, the combination sharedrisk identifier may only be assigned to control plane links whose sharedrisk link group identifier contains the exact same group of shared riskidentifiers. However, a combination shared risk identifier may beapplied to multiple control plane links if the shared risk link groupidentifiers of these control plane links contain the same group ofshared risk identifiers.

As an alternative to assigning a combination shared risk identifier, thenetwork analysis device 115 may be configured to assign priorities toeach shared risk identifier previously assigned. Therefore, if one ormore nodes cannot handle numerous shared risk identifiers, the node maybe configured to drop shared risk identifier associated with lowerpriority risks. Alternatively, the network analysis device 115 may beconfigured to remove shared risk identifiers associated with lowerpriority risks from the physical network database 105.

CONCLUSION

With regard to the processes, systems, methods, heuristics, etc.described herein, it should be understood that, although the steps ofsuch processes, etc. have been described as occurring according to acertain ordered sequence, such processes could be practiced with thedescribed steps performed in an order other than the order describedherein. It further should be understood that certain steps could beperformed simultaneously, that other steps could be added, or thatcertain steps described herein could be omitted. In other words, thedescriptions of processes herein are provided for the purpose ofillustrating certain embodiments, and should in no way be construed soas to limit the claimed invention.

Accordingly, it is to be understood that the above description isintended to be illustrative and not restrictive. Many embodiments andapplications other than the examples provided would be apparent uponreading the above description. The scope of the invention should bedetermined, not with reference to the above description, but shouldinstead be determined with reference to the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isanticipated and intended that future developments will occur in thetechnologies discussed herein, and that the disclosed systems andmethods will be incorporated into such future embodiments. In sum, itshould be understood that the invention is capable of modification andvariation.

All terms used in the claims are intended to be given their broadestreasonable constructions and their ordinary meanings as understood bythose knowledgeable in the technologies described herein unless anexplicit indication to the contrary in made herein. In particular, useof the singular articles such as “a,” “the,” “said,” etc. should be readto recite one or more of the indicated elements unless a claim recitesan explicit limitation to the contrary.

What is claimed is:
 1. A system comprising: a physical network databasestoring information about a plurality of resources in a network, whereineach of the plurality of resources is assigned in the physical networkdatabase to different resource tiers of one or more multi-tier resourcegroups based on a corresponding type of resource, the resource tiersincluding lower and higher tiers with respective lower and higher tierresources; and each lower tier resource at least partially relies on atleast one of the higher tier resources; a policy database storing one ormore policy-based shared risk rules defining diversity requirements forprovisioning the plurality of resources in the network; and a networkanalysis device configured to: analyze a shared risk for each of saidplurality of resources based on at least one of the policy-based sharedrisk rules stored in the policy database that defines a predetermineddistance between and a predetermined length shared by at least two ofsaid plurality of resources and a resource tier for at least a portionof said plurality of resources based on the information stored in thephysical network database, determine whether the policy-based sharedrisk rule is violated based at least in part on at least two of saidplurality of resources being physically and operationally diverse fromone another while being within the predetermined distance of each otherfor the predetermined length and sharing the same resource tier based onthe information stored in the physical network database, and assign ashared risk identifier to each of the at least two resources in thephysical network database in response to the policy-based shared riskrule being violated.
 2. A system as set forth in claim 1, wherein saidshared risk identifier is a policy-based shared risk identifier when thepolicy-based shared risk rule is violated.
 3. A system as set forth inclaim 1, wherein the network analysis device is configured tographically represent said lower tier resources with a first shape andsaid higher tier resources with a second shape, and that at least one ofsaid lower tier resources at least partially relies upon at least one ofsaid higher tier resources with a line there between.
 4. A system as setforth in claim 3, wherein said network analysis device is configured todetermine which of said plurality of lower tier resources rely upon saidhigher tier resource.
 5. A system as set forth in claim 4, wherein theat least two said resources are two of the lower tier resources thatphysically rely upon said at least one of the higher tier resources. 6.A system as set forth in claim 5, wherein said shared risk identifier isa physical shared risk identifier.
 7. A system as set forth in claim 1,wherein the shared risk includes a first shared risk based on thepredetermined distance and the predetermined length, and wherein thenetwork analysis device is configured to identify each resourceassociated with the predetermined distance and the predetermined lengthof the first shared risk and a second predetermined distance and asecond predetermined length of a second shared risk.
 8. A system as setforth in claim 7, wherein the network analysis device is configured todetermine whether all resources associated with the first shared riskare also associated with the second shared risk.
 9. A system as setforth in claim 8, wherein the network analysis device is configured toassign a common risk identifier to each resource associated with thefirst shared risk and the second shared risk.
 10. A system as set forthin claim 9, wherein the common risk identifier represents both the firstrisk and the second risk.
 11. A system as set forth in claim 4, whereinthe set of rules includes an operational shared risk rule that isviolated when the at least two said resources are two of the lower tierresources that operationally rely upon said at least one of the highertier resources.
 12. A system as set forth in claim 11, wherein saidshared risk identifier is an operational shared risk identifier when theoperational shared risk rule is violated.
 13. A system as set forth inclaim 1, wherein physically while being within the predetermineddistance of each other for the predetermined length includes the atleast two resources being physically contained within a third networkresource.
 14. A system as set forth in claim 1, wherein operationallydiverse is when the at least two resources rely upon a third resource tooperate.
 15. A system as set forth in claim 1, wherein violations of thepolicy-based shared risk rule are utilized along with the shared riskidentifiers to determine how data should be routed in the system.
 16. Asystem as set forth in claim 1, wherein the policy-based shared riskrule is violated when the at least two resources are physically andoperationally diverse from one another while being within thepredetermined distance of each other for the predetermined lengthincluding a minimum length.
 17. A system as set forth in claim 1,wherein the predetermined distance is selected from one of no more thantwenty feet and no more than forty feet, and wherein the predeterminedlength includes a minimum length that is selected from one of at leastthirty feet and at least two-hundred feet.
 18. A system as set forth inclaim 1, the network analysis device further being configured toeliminate a shared risked identifier sharing a scope of at least oneresource of said plurality of resources.
 19. A system as set forth inclaim 1, the network analysis device further being configured to assignsaid higher tier resources to each of a first chain and a second chain,wherein at least one of the first and second chains includes said lowertier resources that at least partially relies on the at least one ofsaid higher tier resources.
 20. A system as set forth in claim 1, thenetwork analysis device further being configured to assign at least oneof said first tier resources with the predetermined distance and thepredetermined length and at least one of said second tier resources witha second predetermined distance and a second predetermined length.
 21. Asystem as set forth in claim 1, the network analysis device furtherbeing configured to select the policy-based shared risk rule based inpart on at least two factors selected from a physical factor, anenvironmental factor, and a geographical factor.
 22. A system as setforth in claim 1, the network analysis device further being configuredto select the policy-based shared risk rule based in part on an age ofat least one of said plurality of resources.
 23. A system as set forthin claim 1, the network analysis device further being configured toweigh the shared risk based in part on the predetermined distancebetween at least two of said plurality of resources.
 24. A system as setforth in claim 1, wherein the shared risk identifier is associated witha closed group having at least two of said plurality of resources havingthe same resource tier and violating a same-tier policy-based sharedrisk rule.
 25. A system as set forth in claim 1, wherein the shared riskidentifier is associated with a root-only resource having at least onelower-tier resource of said plurality of resources that does not rely ona higher-tier resource of said plurality of resources.
 26. A methodcomprising: storing, in a physical network database, information about aplurality of resources in a network, wherein each of the plurality ofresources is assigned in the physical network database to differentresource tiers of one or more multi-tier resource groups based on acorresponding type of resource, the resource tiers including lower andhigher tiers with respective lower and higher tier resources, and eachhigher tier resource at least partially relies on at least one of thehigher tier resources; storing, in a policy database, one or morepolicy-based shared risk rules defining diversity requirements forprovisioning the plurality of resources in the network; analyzing ashared risk for each of said plurality of resources based on at leastone of the policy-based shared risk rules that defines a predetermineddistance between and a predetermined length shared by at least two ofsaid plurality of resources and a resource tier for at least a portionof said plurality of resources based on the information stored in thephysical network database; determining whether the policy-based sharedrisk rule is violated based at least in part on at least two of saidplurality of resources being physically and operationally diverse fromone another while being within the predetermined distance of each otherfor the predetermined length and sharing the same resource tier based onthe information stored in the physical network database; and assigning ashared risk identifier to each resource in the physical network databasein response to the policy-based shared risk rule being violated.
 27. Amethod as set forth in claim 26, wherein the shared risk identifier is apolicy-based shared risk identifier when the policy-based shared riskrule is violated.
 28. A method as set forth in claim 26, wherein thenetwork analysis device is configured to graphically represent the lowertier resources with a first shape and the higher tier resources with asecond shape, and that at least one of the lower tier resources at leastpartially relies upon at least one of the higher tier resources with aline therebetween.
 29. A method as set forth in claim 28, furthercomprising determining, with a network analysis device, which of theplurality of lower tier resources at least partially rely upon thehigher tier resource.
 30. A method as set forth in claim 29, wherein theset of rules includes: a physical shared risk rule that is violated whenthe at least two said resources are two of the lower tier resources thatphysically rely upon said at least one of the higher tier resources, andan operational shared risk rule that is violated when the at least twosaid resources are two of the lower tier resources that operationallyrely upon said at least one of the higher tier resources.
 31. A methodas set forth in claim 30, further comprising wherein the shared networkidentifier is a physical shared risk identifier or an operational basedon whether the physical shared risk rule or the operational shared riskrule is violated.
 32. A method as set forth in claim 27, furthercomprising assigning, with the network analysis device, the shared riskidentifier to each of the resources in violation of the policy-basedshared risk rule.
 33. A system comprising: a physical network databasestoring information about a plurality of resources in a network, whereineach of the plurality of resources is assigned in the physical networkdatabase to different resource tiers of one or more multi-tier resourcegroups based on a corresponding type of resource, the resource tiersincluding lower and higher tiers with respective lower and higher tierresources; and each lower tier resource at least partially relies on atleast one of the higher tier resources; a policy database storing one ormore policy-based shared risk rules defining diversity requirements forprovisioning the plurality of resources in the network; and a networkanalysis device configured to: analyze a shared risk for each of saidplurality of resources based on at least one of the policy-based sharedrisk rules stored in the policy database that defines a predetermineddistance between and a predetermined length shared by at least two ofsaid plurality of resource and a resource tier for at least a portion ofsaid plurality of resources based on the information stored in thephysical network database, determine whether the policy-based sharedrisk rule is violated based at least in part on at least two of saidplurality of resources being physically and operationally diverse fromone another while being within a predetermined distance of each otherfor the predetermined length and sharing the same resource tier, andwherein the policy-based shared risk rule includes varying thepredetermined distance based on at least one of a resource type, anenvironment, a geography, and a resource age during the analysis of eachresource based on the information stored in the physical networkdatabase, and assign a shared risk identifier to each of the at leasttwo resources in the physical network database in response to thepolicy-based shared risk rule being violated.